The trend in electronic device production, particularly in integrated circuit technology, has been toward fabricating increasingly larger numbers of discrete circuit elements with higher operating frequencies and smaller circuit element geometries on a single device substrate. After these devices are fabricated, they may be subject to various tests to verify functionality, quantify operating characteristics, and/or characterize the manufacturing process. Additionally or alternatively, the devices may be packaged for communication with other devices and/or electronic components.
Traditionally, these electrical tests have been performed by forming a plurality of electrical contacts with a device under test (DUT), providing electric current to the DUT in the form of input, or test, signals, and receiving electric current or other outputs from the DUT in the form of output, or resultant, signals. The response of the DUT to various input signals and/or power levels may then be quantified through analysis of the input and/or output signals.
However, as a density of the individual circuit elements increases, a density and/or number of bond and/or contact pads, which may be contacted to perform the electrical testing, also may increase. Also, a pitch and/or spacing between adjacent pads may decrease and/or a size of the individual pads may decrease.
This evolution of integrated circuit technology presents unique challenges to the manufacturers of test systems that may be utilized to perform electrical tests. For example, the overall force that is applied to the DUT by the test system may need to be controlled to be below a threshold level despite significant increases in the number of electrical connections that may be made between the test system and the DUT. As another example, a vertical compliance of a probe head assembly that may be utilized to form the electrical connections with the DUT may need to be increased to maintain reliable electrical connection between the probe head assembly and the DUT despite the limitations in the overall force that is applied to the DUT. As yet another example, the nature of the physical interactions between the probe head assembly and the DUT may need to be controlled to provide for reliable electrical connections therebetween. Thus, there exists a need for improved probe head assemblies, probe head assembly components, and methods of operation thereof.